抄録
Polyvinyl alcohol film was cast from a 10% aqueous solution, which was swollen in a 50% ethanol solution and stretched 3 folds, followed by drying and heat-setting at 210°C for 2min. (I-film). It was contracted by 30% by heating at 226°C for 5 sec. in a free state and then dyed with_??_ Congo Red at 70°C (II-film).
II was stretched to the original length at room temperature in a moistened state and again contracted, the amount of contraction being controlled by changing the amount of regain and the temperature (not over 120°C). The dichroic orientation degree fD, X-ray orientation degree fx and the crystallinity X of the film were determined at each stage of the stretching and contraction. From these parameters the stretching degree of the amorphous chain va relative to the isotropic state, was calculated and plotted against the observed fD.
As the results, it was found that fD changes with va nearly reversively by the stretching and the contraction, and the amorphous part deformes according to the Kratky's first deformation mechanism under the experimented conditions.
